The names of the three Border Patrol agents were being withheld late Sunday.

The agent pulled from the river will be hospitalized overnight for observation, Flores said. Agents from a second Border Patrol boat patrolling alongside the capsized vessel issued the call for the missing agents.

Agents in the second Border Patrol boat rescued one of the agents from the capsized boat after hearing a distress call. They were able to retrieve one agent within minutes by throwing out some ropes, Rodriguez said.

At the time of the incident, he said the agents were on a routine mission of deterring illegal entry into the United States as well as intelligence gathering.

Flores said all agents who patrol the river must know how to swim and are tested before assigned to such duty. He said boat crew members typically wear life jackets, but he did not know whether the agent retrieved from the river Sunday or the missing agents had theirs own.